Optineurin is a multifunctional protein, which plays an important role in
the IRF3/7 signaling pathway, an important mechanism through which
the host defends itself against pathogens. The lack of optineurin or his
ubiquitin binding domain results in attenuated activation of TBK1 and
decreased secretion of type 1 interferons. Herpes simplex virus (HSV-1) is
a virus from the alphaherpesviridae family which infects people while
successfully evading the hosts immune response through various
mechanisms. To study the role of optineurin in HSV-1 infection, we
compared the progression of the infection in wild tipe mouse embryonic
fibroblasts, and compared them to mouse embryonic fibroblasts whose
ubiquitin binding domain has been deleted. We noticed that the level of
optineurin in wild type infected cells decreased as the infection progressed
depending on the amount of virus used. This result points to the active
removal of optineurin mediated by the virus. In accordance with the
previously described role of optineurin in the positive regulation TBK1, we
noticed that TBK1 phosphorylation is weaker in cells with lacking
optineurin than in wild type cells. However, viral replication in cells with
mutated optineurin was impeded, despite the impaired TBK1 mediated
interferon activation, compared to wild type cells. Moreover, we did not
notice a significant difference in viral replication in wild type and mutated
cells after the induction of autophagy. The preliminary results in this
study suggest that optineurin facilitates HSV-1 replication, but more
research is needed to clarify the mechanism behind it.